VSL-Intrafor News 2003 N°1

In March 2003, Intrafor has
executed 965 permanent anchors
on a sheet pile curtain within the
soil of the Var River, near Saint-
Laurent-du-Var. The soil composed
of coarse alluvia, sands and
boulders becomes unstable when
employing conventional boring
methods. This necessitated special
Ireland
Dublin Port Tunnel
delivered
> The Dublin Port Tunnel
provided the opportunity for the
Intrafor/Mowlem-Piling
consortium to execute the entire
series of special foundation work
as part of a major European
infrastructure project. Over
50,000 m 2 of diaphragm walls have
been completed (1,200 to 1,500 mm
wall thickness). A work crew of fifty
and no less than four D-wall
excavation grabs and one cutter
assembly were mobilized
simultaneously, and three slurry
treatment plants were used. In
continuity with the diaphragm
walls, a series of tangent piles
1,200 mm in diameter over a linear
distance of 55 m were stayed
throughout the preliminary phase
France
1,000 anchors
in the river
roto-percussion tools with
diameters of between 120 and
146 mm using both a sunken tool
and a tube embedded into the
grouting. An average hourly rate
of one 16-m anchor bored and
installed was achieved. ■
Contact: christophe.allemoz@fr.vslintrafor.com
prior to constructing the concrete
structure. These 16 m-long piles are
anchored into the bedrock.
Additionally, a soil nailed wall
(0 to 12 m-high, 850 m-long)
provides for the provisional support
of the black clays slopes. The studs
(8 to 11 m-long) are drilled with airpercussion
with a daily rate higher
than 200 linear meters: i.e more
than 100 m 2 of shotcrete are
sprayed at the same time. Also
56 high-capacity (2,445-kN) rock
anchors were placed at the toe of
the wall and 210 units of rock bolts
were drilled into the underlying
rock. These works were performed
inside the TBM returning shaft. ■
Contact: daniel.clert@fr.vslintrafor.com
N O T E P A D
Tight frame - VSL in Chile has
been awarded the construction
of a 7 km-long viaduct, for the
metro of Santiago project,
including the supply of
3 launching girders, framework,
post-tensioning and bearings,
to be delivered in Sept. 2004.
Piles on fast track - For the
high-speed rail link Paris-
Strasbourg, Intrafor in a
consortium is driving 276 piles
associated with 9 civil
engineering structures:
4,100 m of boring, amounting to
2,600 m 3 of concrete for piles
reaching depths of 25 m.
Highest wall - At the Collahuasi
Copper mine in the desert near
the border to Bolivia, VSL in
Chile is building a 2,400m 2 VSoL ®
wall at a record-breaking
altitude: 4,500 m.
Jet Grouting columns -
Floodings in northern France in
the winter 2002 have led to
modify a series of locks over the
coming years. Intrafor has
widened an initial lock at Saint-
Valery-sur-Somme and built a
screen using the "Jet Grouting"
technique to shore-up and
water-tighten a dockwall.
Flexible screen - In Mauritius,
the Midlands dam has now been
flooded. For this dam, Intrafor
constructed a 30,000-m 2
diaphragm wall: a flexible
concrete screen to a depth of
14 metres, anchored to the rock.
Airlock boring - Due to a leak
under the foundation raft of a
caisson for the immersed tunnel
underneath the Warnow River in
Rostock, Germany, caused by
damage to the temporary joint
during installation, Intrafor grouted
the raft under very low pressure
(120 kPa) using a low number
of borings of small diameter
(56 mm) and a sealed airlock.
N E W S N ° 1 • 2 0 0 2
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